Dump multiple summons on them. Personally aside from my personal ability to summon high level daedra, I'd consider bringing Gothren's Cephalopod helm and Aryon's Helper to the fight (summon Dremora and summon one of each atronach).

But aside from that I have bound weapons, self fortification spells (fortify speed 100 + fortify strength 100 + fortify long blade 100 + bound longsword is a good one), and my elaborately named Insulated Revelation of the Deadlands. Resist Magicka 100% on self 1s, Weakness to Magicka 100% on touch 1s, Weakness to Fire 100% on touch 1s, Fire Damage 50pts on touch 3s.
Reflected damage you receive is capped at 100pts/second if you are not fortified by any other magical effects, and are really unlucky (all three effects are reflected back onto yourself simultaneously. This is survivable for my mage character as long as I quickly quaff some healing potions or had already cast a battle regeneration spell. However, at up to 600pts of fire damage spread over three seconds it is good enough to kill most things quickly.

Just out of curiosity, since I'm not sure where I'd even find the literature for this, and I'm playing an 80% pure mage right now and would rather not be unpleasantly surprised when I meet a Golden Saint or something similar: What's the behavior of this Absorb spell reflection thing in RC 0.45? Can you toggle it to be one way or the other, or not?

Uselessly for the record, logically speaking I'm with the people who think reflecting Absorb Health should reflect the damage back to you, but NOT heal your opponent. I don't care how OpenMW implements it though, I just want to know so I can figure out how to strategamatize my own playthrough.

As I stated earlier in this thread, the "classic" two-side neutering of reflected Absorb effects is the current set default - you can disable it in Advanced tab of the launcher or directly in settings.cfg. If you do that, reflected Absorb effects shall restore stats of your adversaries while draining yours.

I'm surprised that no one has mentioned this since the discussion started but in Oblivion, Reflect Spell behaves as it does in MCP Morrowind: If you cast Absorb X on something that reflects your spell, the target absorbs your X. This seems to be a vote from Bethesda that MCP Morrowind is the intended behaviour whereas Vanilla Morrowind is bugged. This isn't conclusive evidence but it's still evidence. In fact, I wouldn't be surprised if the MCP implemented this patch after seeing Oblivion's behaviour.

My take is that MCP behaviour should be the default with a config option to enable vanilla behaviour.

When someone presents evidence, the proper response is counter-evidence, not an opinion. That is the Fallacy of Division. We are comparing Oblivion's and Morrowind's magic (specifically Reflect Spell), not the games in their entirety. Comparing only magic, the two games are in fact very similar, with a few magic effects in Morrowind that don't exist in Oblivion being, by far, the biggest difference.

Also, arguing that we should ignore differences between the two games doesn't answer why Bethesda changed the behaviour in the later game to align with the MCP's behaviour? The obvious answer is because the original behaviour was bugged. Is there another explanation?
You say vanilla should be the default. I say, on what basis?

When someone presents evidence, the proper response is counter-evidence, not an opinion. That is the Fallacy of Division. We are comparing Oblivion's and Morrowind's magic (specifically Reflect Spell), not the games in their entirety. Comparing only magic, the two games are in fact very similar, with a few magic effects in Morrowind that don't exist in Oblivion being, by far, the biggest difference.

Also, arguing that we should ignore differences between the two games doesn't answer why Bethesda changed the behaviour in the later game to align with the MCP's behaviour? The obvious answer is because the original behaviour was bugged. Is there another explanation?
You say vanilla should be the default. I say, on what basis?

Oblivion did a lot of things differently from Morrowind. Was it a bug in Morrowind that Absorb spells could be made on target? Because they took that out in Oblivion too. Was it a bug in Morrowind to not include map-based fast travel, going instead for Silt Striders, boats and guild guides? Was it a bug to not include Mark and Recall in Oblivion? Was it a bug that made all attacks in Oblivion hit rather than having a miss chance based on attributes? No, of course not. The design direction changed. "They did it differently in Oblivion" does not mean that the original functionality was a bug.

This isn't a bug fix, and I was more than a bit annoyed that MCP put it under "bugfixes." It's a design decision. As for which is better, the explanation from hrnchamd for why the patch was included was that it makes Absorb overpowered. I happen to disagree, a low magicka cost is what could make an effect like absorb overpowered. Not to mention, something being overpowered doesn't make it a bug. This is about game balancing. Bethedsa chose a different balancing setup for Oblivion, you note. Yeah, and? Why do we care?